Abstract: A process for obtaining the apolar extract comprises: (a) extracting the rhizomes with an organic solvent; (b) filtration and evaporation to dryness of the extract; (c) dissolution of the oleoresin obtained in hot conditions, precipitation while allowing to cool down and filtration of the solid; (d) drying and recrystallizing the solid in order to obtain a product having a purity in curcuminoids higher than 90%. Obtaining the polar extract comprises: (a′) extraction of the rhizomes with water at 50-70° C. and (b′) filtration and evaporation of the water. Application of the compositions and preparations as catchers of free radicals and antiageing agents, as well as reducing agents to reduce the plasma levels of lipid peroxides in human beings are disclosed.